JPS57138885A - Controlling device for chopper - Google Patents

Abstract

PURPOSE:To improve the controllability of a chopper by gradually varying the ON pulse for a regeneratively braking chopper by a digital computer and smoothly switching between the regenerative brake and the regenerative brake, thereby suppressing the vibration of a filter capacitor voltage. CONSTITUTION:A timer 1 produces a trigger signal to an arithmetic controller 2 at every sampling periodic interval, an input unit 3 inputs a switching signal from regenerative brake to a generative brake or a return signal vice versa, and outputs an output to a memory 4. When an arithmetic controller 2 executes two brake mode switching or returning program by the condition information such as the switching signal or the returning signal from the memory 4, the number beta of pulses corresponding to the extincting region of a generative brake chopper BCH at the sampling period interval and the gate command are outputted to a digital phase shifter 5, and when the gate command is ''1'', the phase shift and width of an ON pulse synchronized with the chopper frequency are determined on the basis of the beta, and are outputted to the gate of the BCH via a pulse amplifier circuit 6.